The present invention relates to a video game device. More particularly, this invention relates to a game device which is installed at amusement centers or at home and which is capable of expressing more realistic pictures.
With the progress of computer technology, video game devices utilizing computer graphics technology have come to be widely used. This type of video game devices are widely accepted by users. A large number of various kinds of game devices have been devised and various game software products which run on such game devices have been supplied.
It is desirable that pictures be displayed in more realistic expressions on a screen so that users would be able to enjoy video games fully. For example, with a vehicle race such as a car race, it is desirable that movements of cars and the background be expressed naturally and that anything which may occur during the drive, for example, reflection of light on a windshield be expressed as special effects on a screen. Moreover, it will be interesting if traces of tire slips of a car appear.
On the other hand, since complicated arithmetic operations such as coordinate transformation are repeated for three-dimensional screen display, the amount of operation borne by CPU becomes enormous. Accordingly, if special effects or the like of picture expressions are performed, the number of polygons to be displayed on the screen must be decreased by the amount of operation to be used for such special effects.
Therefore, it is a first object of this invention to provide a video game device capable of expressing a picture with which a game player can perceive dazzling light from a light source.
It is a second object of this invention to provide a game device capable of expressing, on a screen, traces of a moving object in a video game.
It is a third object of this invention to provide a method of decreasing the amount of operation in a drawing routine when developments of a game in the three-dimensional virtual space are displayed on a two-dimensional screen so that pictures on the screen may seem to be three-dimensional.
In order to achieve the above-mentioned objects, a game device of the present invention displays a picture of a scene that has come into view by moving a visual point of a virtual camera in a three-dimensional virtual space, and the game device comprises a flare processing means (S102 through S118) for forming a flare in a picture when light source exists within view. The flare processing means comprises: a line-of-sight vector generating means (S106) for obtaining a line-of-sight vector which shows a, line-of-sight direction of the visual point; a ray vector generating means (S104) for obtaining a ray vector which shows-a direction of the light source from the visual point; an inner product calculating means (S108) for calculating an inner product of the line-of-sight vector and the ray vector; and a flare forming means (S112 through S118) for forming a flare having intensity according to the inner product in the picture. This makes it possible to form a flare in accordance with the position of the light source from the visual point and/or the intensity of the light source. Expressions are made more closer to real scenes and it is possible to form game pictures with strengthened image effects, thereby making a game more amusing.
The game device of this invention further comprises a determining means (S110) for activating the flare forming means on the basis of the results of comparison of the inner product with a reference value. This makes it possible to prevent lowering of the picture quality by avoiding the formation of flares and performing flare processing when the intensity of the light-source is not strong enough to generate flares.
The flare forming means increases a degree of whiteness of the picture in accordance with the inner product (S112). This causes an influence (or flare effect) of the flares upon the picture to be expressed.
The flare forming means forms a picture of flare polygons having transparency according to the inner product (S114, S118). This makes it possible to express flares of a camera lens.
The flare forming means conducts, with the inner product being between a predetermined upper limit and a predetermined lower limit, at least any one of the processing to add whiteness to the picture according to the inner product and the processing to form a flare polygon having transparency according to the inner product. This makes it possible to avoid formation of flares with a light source having weak intensity and to avoid excessive flare processing with a light source having strong intensity.
The flare forming means forms the flare on a straight line linking the visual point with the light source (S116, S118). This makes it possible to express the incidence of rays into a virtual camera.
A game device of this invention is a game device for displaying, as a picture, a scene having come into view by moving a visual point in a three dimensional virtual space. The game device comprises a flare processing means for forming a flare in the picture when a light source exists within view of the visual point The flare processing means determines a flare degree in accordance with the likes of a position of the light source within view and intensity of the light source. In doing so, it is possible to determine the flare degree at an appropriate value by using a table or a function in consideration of the above-mentioned upper limit and lower limit or the like.
The flares are expressed by, for example, displaying on a screen a flat figure having a comparatively higher degree of whiteness than that of the background or a hollow flat figure. Repeating display and no display of the flares in a short period of time, that is, flashing makes it possible to make it look like a real situation of flare formation. Moreover, it is possible to avoid continuous obstruction on a picture of the background by flares (particularly, flare pictures which are not hollow), thereby avoiding interruption with operation of a game.
It is possible to make the flares look like real ones by displaying a plurality of flares on a straight line corresponding to an incident ray. In doing so, it is possible to reduce a burden on arithmetic operation by forming a plurality of flares to be displayed by using similar figures.
The light source is a virtual sun located in the three-dimensional virtual space. The virtual sun is relocated from a normal position to a position within view of a predetermined scene in order to generate the flare in the picture on the predetermined scene. This makes it possible to dramatically present a game scene by intentionally causing the light source to exist in the game scene and by generating flares.
A game device of this invention is a game device for displaying, as a picture, an object moving in accordance with developments of a game. The game device comprises: a means (S132) for reading a present position of the object; and a trace mark drawing means (S132 through S158) for drawing a trace mark in length within a predetermined range from the present position and for extinguishing a bottom position of the trace mark by making it gradually lighter in color with the lapse of time. This makes it possible to reduce the amount of operation for picture processing by reducing trace polygons of, for example, tires.
It is preferable that the trace mark consist of plural portions, each portion having an assigned pattern which becomes lighter in color from a top position of the trace mark toward a bottom position of the trace mark. As the trace pattern assigned to each portion, a previously formed pattern can be used. It is possible to change the transparency of a basic trace pattern and use it as a pattern for each portion.
The trace mark drawing means extends only the top position of the trace mark (S142 through S152) when the present position of said object is located less than a predetermined value apart from the top position of the drawn trace mark (S134), and the trace mark drawing means moves, by the predetermined value, the trace mark in its entirety toward the present position of the object (S136 through S158) when the present position of the object is located not less than the predetermined value apart from the top position of the drawn trace mark. This makes it possible to draw the trace mark which will not give a sense of incompatibility to a game player, and to limit the length of the trace mark in its entirety to a constant length and restrain the amount of operation for the picture processing from increasing.
The trace mark drawing means adjusts the timing to extinguish the drawn trace according to a moving speed of the object (S132 through S158).
The trace mark drawing means does not extinguish the drawn trace mark when the object stands still, while the trace mark drawing means extinguishes the drawn trace mark quickly at a speed according to a moving speed of the object when the object is moving (S132 through S158). This allows the trace mark to follow the movements of the object.
Moreover, it is preferable that the trace mark drawing means delete the drawn trace mark when the object stops and a predetermined amount of time has passed. This makes it possible to reduce the number of display polygons (or slip traces) and to lessen a burden on the operation of the CPU.
The trace mark drawing means has: a cyclic register (as shown in FIG. 10) for retaining positions of respective portions of a mark, which consists of the plural portions (as shown in FIG. 9), in a plurality of storage regions which respectively correspond to the respective portions of the mark; and a mark top position indicating means (as shown in FIGS. 6 and 8) for indicating a storage region of the cyclic register, which corresponds to the top position of mark.
A medium of this invention stores a program for making a computer system function as a game device as described above.
A method of forming picture data of this invention comprises the steps of: locating an object composed of polygons in a three-dimensional virtual space (S202); setting a visual point in the three-dimensional virtual space and forming a projected picture by projecting polygons in a display region as seen from this visual point on a plane of projection (S254); identifying whether each polygon is visible or invisible from the visual point according to the projected picture formed on the plane of projection (S256); forming object data from data showing whether each polygon is visible or invisible (S212); and relating the visual point with the object data (S216).
A method of forming picture data of this invention comprises the steps of: locating all objects composed of polygons in a three-dimensional space (S202); setting a plurality of visual points in the three-dimensional space (S204); forming a projected picture for each visual point by projecting, on a plane of projection for each visual point, the polygons within a display region as seen from each visual point (S252, S254); identifying whether each polygon is visible or invisible from each visual point according to the projected picture formed on the plane of projection (S256); forming data showing whether each polygon is visible or invisible from each visual point on the basis of the results of the identification (S258); forming a plurality of object data by making the same or similar patterns into a group in accordance with a data pattern of each polygon, the data representing whether the polygon is visible or invisible from each visual point (S212); and forming an object table representing object data which can be seen from each visual point (S216).
A medium of this invention stores a program for having a computer system execute each step of the above-described method of forming picture data.